Published by Is It Down Right Now Technical Team • Updated August 2026

What Causes DNS Lookup Failures?

The Domain Name System (DNS) acts as the phonebook of the internet. When you type a domain name like google.com into your browser, your device asks a DNS server to translate that readable name into a numeric IP address (such as 142.250.190.46).

If our Is It Down Right Now status checker indicates the target website is UP, but your browser shows a DNS error, the problem is localized to your computer, router, or your Internet Service Provider's (ISP) default DNS servers.

Step 1: Flush Your Operating System DNS Cache

Operating systems save previously resolved domain names in a local cache. If a website recently migrated servers or changed IP addresses, your computer might be trying to connect to a stale or invalid IP.

On Windows (11, 10, 8, 7):

1. Press Win + S, type cmd, right-click Command Prompt and select Run as administrator.
2. Type the following command and hit Enter:

You should see the message: "Successfully flushed the DNS Resolver Cache."

To refresh your network IP configuration completely, you can also run:

On macOS:

1. Open Terminal (via Spotlight by pressing Cmd + Space and typing Terminal).
2. Paste the command below and press Enter (enter your administrator password when prompted):

Step 2: Switch to Fast, Reliable Public DNS Resolvers

Many ISPs provide slow or unreliable default DNS servers that frequently suffer from resolution timeouts or regional caching bugs. Switching to free, globally distributed public DNS providers will significantly improve website availability and loading speeds.

How to Change DNS Settings on Windows 10/11:

1. Open Settings > Network & internet > Advanced network settings > More network adapter options.
2. Right-click your active connection (Wi-Fi or Ethernet) and select Properties.
3. Select Internet Protocol Version 4 (TCP/IPv4) and click Properties.
4. Select Use the following DNS server addresses.
5. Enter 1.1.1.1 as Preferred DNS server and 8.8.8.8 as Alternate DNS server.
6. Click OK and restart your browser.

Step 3: Clear Google Chrome's Internal DNS Cache

Google Chrome maintains its own independent DNS cache separate from the operating system.

1. In Chrome's address bar, type: chrome://net-internals/#dns and press Enter.
2. Click the Clear host cache button.
3. Next, navigate to chrome://net-internals/#sockets and click Flush socket pools.
4. Restart your browser and re-test the website.

Step 4: Restart Your Wi-Fi Router / Modem

Routers have internal memory and DNS forwarders that can become overwhelmed or corrupted after weeks of continuous uptime. Unplug your router's power cable, wait 30 seconds, and plug it back in. This forces the device to establish a fresh connection with your ISP.